Qualitative PCR Method for Roundup Ready® Soybean: Interlaboratory Study

Abstract

Quantitative and qualitative methods based on PCR have been developed for genetically modified organisms (GMO). Interlaboratory studies were previously conducted for GMO quantitative methods; in this study, an interlaboratory study was conducted for a qualitative method for a GM soybean, Roundup Ready® soy (RR soy), with primer pairs designed for the quantitative method of RR soy studied previously. Fourteen laboratories in Japan participated. Each participant extracted DNA from 1.0 g each of the soy samples containing 0, 0.05, and 0.10% of RR soy, and performed PCR with primer pairs for an internal control gene (Le1) and RR soy followed by agarose gel electrophoresis. The PCR product amplified in this PCR system for Le1 was detected from all samples. The sensitivity, specificity, and false-negative and false-positive rates of the method were obtained from the results of RR soy detection. False-negative rates at the level of 0.05 and 0.10% of the RR soy samples were 6.0 and 2.3%, respectively, revealing that the LOD of the method was somewhat below 0.10%. The current study demonstrated that the qualitative method would be practical for monitoring the labeling system of GM soy in kernel lots.

Rapid Screening Detection of Genetically Modified Crops by Loop-Mediated Isothermal Amplification with a Lateral Flow Dipstick

“…The LODs of the two GM maize events and all GM soybean events, targeting P35S, tE9, and Cry1Ab/Cry1Ac, were lower than those of the previous methods. Among other of our previous reports using PCR, conventional PCR analyses showed that the LOD of RRS targeting a construct specific region was 0.1%, and the LOD of MON810 targeting P35S was 0.2% . We have also developed a real-time PCR array method for comprehensive GM detection .…”

“…The developed method was demonstrated to be rapid and cost-effective, and the LODs of the methods were at the same level as or lower than those in our previously reported qualitative detection method including LAMP analyses. 14,24,26 The LODs of the developed methods were equal to or less than 0.5% for all targets, indicating that the developed methods are available not only for Japan but also other countries or areas such as the EU, Australia, New Zealand, and Korea in terms of the level of GM content. Therefore, we conclude that the developed method would be applicable for monitoring the validity of the food labeling system in many situations, including on-site inspection.…”

Applicability of Plasmid Calibrant pTC1507 in Quantification of TC1507 Maize: An Interlaboratory Study

“…Cf was calculated as the ratio of the copy number of event-specific targets to the copy number of the endogenous gene. 21 The differences of quantification results among all eight participating laboratories were statistically analyzed. The mean Cf values from the eight laboratories ranged from 0.38 to1.37 with SD ranging from 0.04 to 0.262 and RSD rangingfrom 7.39 to 23.09% (Table 3).…”

“…17−19 Two plasmid calibrants have been validated for the detection of Roundup Ready soybean event GTS-40-3-2 by interlaboratory ring trials. 20,21 Three other plasmid calibrants, ERM-AD413, ERM-AD415, and ERM-AD427, have also been certified and commercialized worldwide by IRMM. 11−13 International collaborative validation is the prerequisite step for proposing a CRM for a GMO.…”

“…Because of their convenience and low cost, plasmid calibrants have been considered a good substitute for CRMs using raw plant materials. To date, more than 20 plasmid calibrants have been successfully constructed and used for the detection and quantification of several GM maize, soybean, and cotton events. − Two plasmid calibrants have been validated for the detection of Roundup Ready soybean event GTS-40-3-2 by interlaboratory ring trials. , Three other plasmid calibrants, ERM-AD413, ERM-AD415, and ERM-AD427, have also been certified and commercialized worldwide by IRMM. − …”